Airbag control unit with part number 65.77-5A1FC46-01

What does the airbag control unit 65.77-5A1FC46-01 do?

The airbag control unit 65.77-5A1FC46-01 is the central control unit of the restraint system (SRS) for BMW. It processes the signals from the crash sensors and, in the event of an accident, decides within milliseconds which airbags and seatbelt pretensioners are triggered.

The airbag warning light in the instrument cluster shows faults in the system that the control unit detects continuously.

After an accident, the unit stores crash data and locks itself. The lock is only lifted by the repair.

Why does the control unit 65.77-5A1FC46-01 fail?

Crash data stored after an accident is the most common cause, even if no airbag has been triggered; a normal diagnostic tool cannot erase it. Other possible causes are aged electronic components, cold solder joints, moisture and corrosion at plug connections, and voltage spikes.

The crash data stays stored until Airbag24 removes it during the repair. The fault memory therefore cannot be reset by common means.

Aged components and cold solder joints may not show from the outside. Moisture, corrosion and voltage spikes, for example from a jump start, on the other hand put a strain on plugs and electronics.

How can you tell that the 65.77-5A1FC46-01 is defective?

The first sign is the airbag warning light in the instrument cluster, which lights up permanently or intermittently. Other signs are a fault message in the instrument cluster, no connection between the diagnostic tool and the control unit, and a fault memory that cannot be erased. In that case, airbags and seatbelt pretensioners may not trigger in an emergency.

The warning light shows the defect, whether it occurs continuously or only now and then. If it then turns yellow or red when the ignition is switched on, that is a clear signal to have the fault memory read out.

Which vehicles is the 65.77-5A1FC46-01 fitted in?

The control unit 65.77-5A1FC46-01 is fitted in these vehicles: BMW 1 Series F40 (2019-2024).

The overview below shows the vehicles listed for this part number.

• BMW 1 Series F40 (2019-2024)

Compare the part number on the label of the removed unit with this page to confirm that you have the right unit. Whether the control unit itself is defective or a plug or cable is the cause is only decided by reading out the fault memory. Have it read out before removal.

For the same vehicles, we also repair control units with the part numbers 65779873895, 9873895, A2C16862603.

How does the repair of the 65.77-5A1FC46-01 work?

First, have the fault memory read out and enclose the report. Then disconnect the battery before the control unit is removed, and create a repair order online. After that, send in the well-packed unit. Airbag24 checks it on the test bench, replaces defective components, erases stored crash data and carries out a function test; processing usually takes 3–4 working days.

This order is for your safety. The report records the state of the system before removal.

Afterwards, your own repaired control unit is sent back to you.

Our repairs come with 2 years' statutory liability for defects.

The repaired control unit comes back with all vehicle data and is ready for use as soon as it is refitted — no coding or programming is required.

How does the control unit 65.77-5A1FC46-01 get to Airbag24?

You send the unit in as a parcel or book a UPS collection for an extra charge. After the repair, Airbag24 returns it to you by UPS.

Put the printed repair order in the parcel and pack the unit shock-proof.